Venous disease is a main cause of pressure ulcers such as, for example, leg ulcers. Venous disease occurs when the valves in the circulatory system that control the flow of blood up the leg, as it travels from the foot to the heart, become damaged. If the valves are damaged the blood can backflow causing high pressure in the veins. Under these conditions fluids that are normally retained in the veins leak out, resulting in swelling in the legs. This swelling prevents oxygen, which is carried in the blood and necessary for the healing process, from reaching the wound site.
By way of further details and definitions, the two major superficial veins of the lower extremities are the great saphenous and small saphenous veins. The great saphenous vein, a superficial vein, runs generally medially and distally from the knee to the foot. The small saphenous vein continues into the foot and runs posteriorly and inferiorly with respect to the lateral malleolus. The great saphenous vein runs anteriorly and in proximity to the medial malleolus joining the posterior arch vein which runs posteriorly and inferiorly to the medial malleolus. The great saphenous vein communicates with the dorsal venous arch, a superficial vein of the foot.
The superficial veins are generally near the surface and communicate with deep veins which are further from the surface. Perforating veins are the veins which connect the superficial veins to the deep veins. The deep veins of the foot include the deep plantar venous arch, the medial and lateral plantar veins, and the posterior tibial veins. The deep veins of the leg include the posterior tibial veins, the peroneal veins and the anterior tibial veins. The fascia is a sheet or band of tissue which connects the muscle and deep veins and holds them together. The perforating veins are communications between the superficial veins (above the deep fascia and near the skin) and the deep veins below the fascia. The deep and superficial veins possess valves which permit unidirectional flow in the direction of the heart. The perforating veins also possess valves which permit unidirectional blood flow from the superficial veins to the deep veins. The perforating veins pass through the fascia. Venous return to the heart is assisted by the pumping action of the muscles which compress the deep veins and force blood toward the heart during contraction. If the valves in the perforating veins become incompetent or if the deep veins become blocked, pressure in the superficial veins increases resulting in hyperpigmentation, eczema, edema, varicosities and/or skin ulcerations. As a result venous ulcers occur in the lower limbs of patients resulting from venous insufficiency due to deep vein thrombosis and failure of the venous valves that normally act during muscle contraction to prevent blood backflow.
The result of chronic venous insufficiency at the ankle level has traditionally been that of chronic swelling, thickening of the skin, discoloration of the skin, and ultimately ulceration. Venous stasis ulcers appear as skin ulcerations on the lower extremities of a person, i.e. the leg, ankle or foot and in particular in a location posterior to the malleolus. One cause of venous stasis is valvular insufficiency in the deep veins, perforating veins and superficial veins. Stasis means a stoppage of flow of blood. Impaired blood flow interferes with normal healing and prolongs repair. Patient care therefore centers on preventing infection, increasing blood flow to deep veins, and decreasing pressure to superficial veins.
Compression therapy is often used to treat and/or prevent venous ulcers with the rationale that if the excess fluid can be squeezed out, oxygen can return and facilitate the healing of the wound. Compression therapy involves wrapping the leg with elastic bandages that apply a constant uniform pressure. For the best treatment the wrapping is applied so there is approximately 20-40 mmHg of pressure. However, as every leg is different this can be difficult to achieve.
There still exists a need for a device for treating pressure ulcers, for example, venous ulcers and similar pathology which accurately and reliably provides the appropriate wound care, compression force and provides a measure of the pressure being applied.